Non-coding RNA which includes microRNAs (miRNA) and long non-coding RNAs (lncRNA) are RNA molecules that serve as transcriptional and post-transcriptional gene repressors in eukaryotic cells that have been implicated in the regulation of malignant behavior in cancer cells, such as invasion and metastasis. Non- coding RNAs are suspected to play an instrumental role in cancer initiation by regulating the cancer stem cell (CSC) state. This proposal aims to identify miRNAs and lncRNAs involved in salivary tumor initiation and progression. Using microarray assays, the expression levels of around 1000 plus miRNAs and 32,000 plus lncRNA currently identified in humans will be determined in normal, benign, and malignant salivary gland tumors. Our central hypothesis is that dysregulation of specific miRNAs and lncRNAs in normal salivary cell pathways result in a variety of salivary tumors. In order to address this, we will follow 3 specific aims. The first is to generate microRNA and lncRNA profiles in normal salivary glands, benign and malignant tumors to identify a panel of miRNAs that are differentially expressed among these three populations.
The second aim i s to manipulate the expression of these microRNAs and lncRNAs in vitro to determine their role in cell proliferation, invasion, self-renewal, and regulation of stem cell genes. The third is investigate the role of these RNAs in a mouse model of salivary tumors. We hypothesize that the dysregulation of a specific set of miRNAs and lncRNAs in salivary gland cells could confer on these cells, properties of CSCs including the ability to self-renew, differentiate, initiate tumors, and the ability to invade and metastasize. Identifying key molecular differences in miRNA and lncRNA expression among normal salivary gland, benign and malignant salivary tumors will result in discovering genes and events associated with salivary tumor and cancer initiation. These studies are novel because the global profiling of salivary tumors to identify key miRNAs and lncRNAs that are dysregulated and that may have a key role in tumorigenesis and oncogenesis has not previously been addressed. By identifying these dysregulated non-coding RNAs, we would then be able to characterize these miRNAs and lncRNAs to elucidate their role in the generation of the tumor and cancer-initiating cells in this disease. If successful, this stuy would reveal molecular targets that could prove useful in the diagnosis and treatment of salivary tumors and cancer.

Public Health Relevance

Non-coding RNAs include microRNAs (miRNAs), small, non-coding RNA molecules that serve as post- transcriptional gene repressors in eukaryotic cells and long non-coding RNAs (lncRNAs), RNAs that regulate gene expression at the level of chromatin modification, transcription, and post-transcriptional processing, that have been implicated in the regulation of behavior in cancer cells, such as cancer initiation, invasion, and metastasis. In this proposal, we wish to identify non-coding RNAs in salivary glands that are responsible for tumorigenesis and oncogenesis. We will investigate how manipulation of the identified non-coding RNAs in salivary glands will regulate pathogenesis of salivary tumors in vitro and in vivo.